Re: [PATCH] PCI and PCI Hotplug update for 2.6.6-rc1

Greg KH
2004-04-15T17:32:05Z

ChangeSet 1.1692.3.1, 2004/03/26 16:11:41-08:00, greg@kroah.com

PCI: add ability to access pci extended config space for PCI Express devices

Patch originally written by Intel, cleaned up and made sane by
Matthew Wilcox <willy@debian.org> and then tweaked a bit more by me.

>From Matt's original email:
- Add cfg_size to struct pci_dev.
- Use it in sysfs and procfs.
- Introduce pci_find_ext_capability() for finding extended capabilities.
- Change the PCI_X_STATUS defines to match the spec (mea culpa there).
- Add defines for the extended capabilities.

drivers/pci/pci-sysfs.c | 29 ++++++++++----
drivers/pci/pci.c | 58 ++++++++++++++++++++++++----
drivers/pci/probe.c | 40 +++++++++++++++++++
drivers/pci/proc.c | 26 ++++++------
include/linux/pci.h | 99 ++++++++++++++++++++++++++++++++++++++++++------
5 files changed, 212 insertions(+), 40 deletions(-)

diff -Nru a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
--- a/drivers/pci/pci-sysfs.c Thu Apr 15 10:06:45 2004
+++ b/drivers/pci/pci-sysfs.c Thu Apr 15 10:06:45 2004
@@ -1,8 +1,8 @@
/*
* drivers/pci/pci-sysfs.c
*
- * (C) Copyright 2002 Greg Kroah-Hartman
- * (C) Copyright 2002 IBM Corp.
+ * (C) Copyright 2002-2004 Greg Kroah-Hartman <greg@kroah.com>
+ * (C) Copyright 2002-2004 IBM Corp.
* (C) Copyright 2003 Matthew Wilcox
* (C) Copyright 2003 Hewlett-Packard
*
@@ -71,7 +71,7 @@

/* Several chips lock up trying to read undefined config space */
if (capable(CAP_SYS_ADMIN)) {
- size = 256;
+ size = dev->cfg_size;
} else if (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS) {
size = 128;
}
@@ -123,10 +123,10 @@
unsigned int size = count;
loff_t init_off = off;

- if (off > 256)
+ if (off > dev->cfg_size)
return 0;
- if (off + count > 256) {
- size = 256 - off;
+ if (off + count > dev->cfg_size) {
+ size = dev->cfg_size - off;
count = size;
}

@@ -167,6 +167,17 @@
.write = pci_write_config,
};

+static struct bin_attribute pcie_config_attr = {
+ .attr = {
+ .name = "config",
+ .mode = S_IRUGO | S_IWUSR,
+ .owner = THIS_MODULE,
+ },
+ .size = 4096,
+ .read = pci_read_config,
+ .write = pci_write_config,
+};
+
void pci_create_sysfs_dev_files (struct pci_dev *pdev)
{
struct device *dev = &pdev->dev;
@@ -179,7 +190,11 @@
device_create_file (dev, &dev_attr_class);
device_create_file (dev, &dev_attr_irq);
device_create_file (dev, &dev_attr_resource);
- sysfs_create_bin_file(&dev->kobj, &pci_config_attr);
+
+ if (pdev->cfg_size < 4096)
+ sysfs_create_bin_file(&dev->kobj, &pci_config_attr);
+ else
+ sysfs_create_bin_file(&dev->kobj, &pcie_config_attr);

/* add platform-specific attributes */
pcibios_add_platform_entries(pdev);
diff -Nru a/drivers/pci/pci.c b/drivers/pci/pci.c
--- a/drivers/pci/pci.c Thu Apr 15 10:06:45 2004
+++ b/drivers/pci/pci.c Thu Apr 15 10:06:45 2004
@@ -111,21 +111,15 @@
* support it. Possible values for @cap:
*
* %PCI_CAP_ID_PM Power Management
- *
* %PCI_CAP_ID_AGP Accelerated Graphics Port
- *
* %PCI_CAP_ID_VPD Vital Product Data
- *
* %PCI_CAP_ID_SLOTID Slot Identification
- *
* %PCI_CAP_ID_MSI Message Signalled Interrupts
- *
* %PCI_CAP_ID_CHSWP CompactPCI HotSwap
- *
* %PCI_CAP_ID_PCIX PCI-X
+ * %PCI_CAP_ID_EXP PCI Express
*/
-int
-pci_find_capability(struct pci_dev *dev, int cap)
+int pci_find_capability(struct pci_dev *dev, int cap)
{
return __pci_bus_find_cap(dev->bus, dev->devfn, dev->hdr_type, cap);
}
@@ -150,6 +144,54 @@
pci_bus_read_config_byte(bus, devfn, PCI_HEADER_TYPE, &hdr_type);

return __pci_bus_find_cap(bus, devfn, hdr_type & 0x7f, cap);
+}
+
+/**
+ * pci_find_ext_capability - Find an extended capability
+ * @dev: PCI device to query
+ * @cap: capability code
+ *
+ * Returns the address of the requested extended capability structure
+ * within the device's PCI configuration space or 0 if the device does
+ * not support it. Possible values for @cap:
+ *
+ * %PCI_EXT_CAP_ID_ERR Advanced Error Reporting
+ * %PCI_EXT_CAP_ID_VC Virtual Channel
+ * %PCI_EXT_CAP_ID_DSN Device Serial Number
+ * %PCI_EXT_CAP_ID_PWR Power Budgeting
+ */
+int pci_find_ext_capability(struct pci_dev *dev, int cap)
+{
+ u32 header;
+ int ttl = 480; /* 3840 bytes, minimum 8 bytes per capability */
+ int pos = 0x100;
+
+ if (dev->cfg_size <= 256)
+ return 0;
+
+ if (pci_read_config_dword(dev, pos, &header) != PCIBIOS_SUCCESSFUL)
+ return 0;
+
+ /*
+ * If we have no capabilities, this is indicated by cap ID,
+ * cap version and next pointer all being 0.
+ */
+ if (header == 0)
+ return 0;
+
+ while (ttl-- > 0) {
+ if (PCI_EXT_CAP_ID(header) == cap)
+ return pos;
+
+ pos = PCI_EXT_CAP_NEXT(header);
+ if (pos < 0x100)
+ break;
+
+ if (pci_read_config_dword(dev, pos, &header) != PCIBIOS_SUCCESSFUL)
+ break;
+ }
+
+ return 0;
}

/**
diff -Nru a/drivers/pci/probe.c b/drivers/pci/probe.c
--- a/drivers/pci/probe.c Thu Apr 15 10:06:45 2004
+++ b/drivers/pci/probe.c Thu Apr 15 10:06:45 2004
@@ -18,6 +18,8 @@

#define CARDBUS_LATENCY_TIMER 176 /* secondary latency timer */
#define CARDBUS_RESERVE_BUSNR 3
+#define PCI_CFG_SPACE_SIZE 256
+#define PCI_CFG_SPACE_EXP_SIZE 4096

/* Ugh. Need to stop exporting this to modules. */
LIST_HEAD(pci_root_buses);
@@ -530,6 +532,43 @@
kfree(pci_dev);
}

+/**
+ * pci_cfg_space_size - get the configuration space size of the PCI device.
+ *
+ * Regular PCI devices have 256 bytes, but PCI-X 2 and PCI Express devices
+ * have 4096 bytes. Even if the device is capable, that doesn't mean we can
+ * access it. Maybe we don't have a way to generate extended config space
+ * accesses, or the device is behind a reverse Express bridge. So we try
+ * reading the dword at 0x100 which must either be 0 or a valid extended
+ * capability header.
+ */
+static int pci_cfg_space_size(struct pci_dev *dev)
+{
+ int pos;
+ u32 status;
+
+ pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
+ if (!pos) {
+ pos = pci_find_capability(dev, PCI_CAP_ID_PCIX);
+ if (!pos)
+ goto fail;
+
+ pci_read_config_dword(dev, pos + PCI_X_STATUS, &status);
+ if (!(status & (PCI_X_STATUS_266MHZ | PCI_X_STATUS_533MHZ)))
+ goto fail;
+ }
+
+ if (pci_read_config_dword(dev, 256, &status) != PCIBIOS_SUCCESSFUL)
+ goto fail;
+ if (status == 0xffffffff)
+ goto fail;
+
+ return PCI_CFG_SPACE_EXP_SIZE;
+
+ fail:
+ return PCI_CFG_SPACE_SIZE;
+}
+
/*
* Read the config data for a PCI device, sanity-check it
* and fill in the dev structure...
@@ -566,6 +605,7 @@
dev->multifunction = !!(hdr_type & 0x80);
dev->vendor = l & 0xffff;
dev->device = (l >> 16) & 0xffff;
+ dev->cfg_size = pci_cfg_space_size(dev);

/* Assume 32-bit PCI; let 64-bit PCI cards (which are far rarer)
set this higher, assuming the system even supports it. */
diff -Nru a/drivers/pci/proc.c b/drivers/pci/proc.c
--- a/drivers/pci/proc.c Thu Apr 15 10:06:45 2004
+++ b/drivers/pci/proc.c Thu Apr 15 10:06:45 2004
@@ -16,16 +16,15 @@
#include <asm/uaccess.h>
#include <asm/byteorder.h>

-#define PCI_CFG_SPACE_SIZE 256
-
static int proc_initialized; /* = 0 */

static loff_t
proc_bus_pci_lseek(struct file *file, loff_t off, int whence)
{
loff_t new = -1;
+ struct inode *inode = file->f_dentry->d_inode;

- down(&file->f_dentry->d_inode->i_sem);
+ down(&inode->i_sem);
switch (whence) {
case 0:
new = off;
@@ -34,14 +33,14 @@
new = file->f_pos + off;
break;
case 2:
- new = PCI_CFG_SPACE_SIZE + off;
+ new = inode->i_size + off;
break;
}
- if (new < 0 || new > PCI_CFG_SPACE_SIZE)
+ if (new < 0 || new > inode->i_size)
new = -EINVAL;
else
file->f_pos = new;
- up(&file->f_dentry->d_inode->i_sem);
+ up(&inode->i_sem);
return new;
}

@@ -61,7 +60,7 @@
*/

if (capable(CAP_SYS_ADMIN))
- size = PCI_CFG_SPACE_SIZE;
+ size = dev->cfg_size;
else if (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS)
size = 128;
else
@@ -134,14 +133,15 @@
const struct proc_dir_entry *dp = PDE(ino);
struct pci_dev *dev = dp->data;
int pos = *ppos;
+ int size = dev->cfg_size;
int cnt;

- if (pos >= PCI_CFG_SPACE_SIZE)
+ if (pos >= size)
return 0;
- if (nbytes >= PCI_CFG_SPACE_SIZE)
- nbytes = PCI_CFG_SPACE_SIZE;
- if (pos + nbytes > PCI_CFG_SPACE_SIZE)
- nbytes = PCI_CFG_SPACE_SIZE - pos;
+ if (nbytes >= size)
+ nbytes = size;
+ if (pos + nbytes > size)
+ nbytes = size - pos;
cnt = nbytes;

if (!access_ok(VERIFY_READ, buf, cnt))
@@ -403,7 +403,7 @@
return -ENOMEM;
e->proc_fops = &proc_bus_pci_operations;
e->data = dev;
- e->size = PCI_CFG_SPACE_SIZE;
+ e->size = dev->cfg_size;

return 0;
}
diff -Nru a/include/linux/pci.h b/include/linux/pci.h
--- a/include/linux/pci.h Thu Apr 15 10:06:45 2004
+++ b/include/linux/pci.h Thu Apr 15 10:06:45 2004
@@ -305,18 +305,89 @@
#define PCI_X_CMD_ERO 0x0002 /* Enable Relaxed Ordering */
#define PCI_X_CMD_MAX_READ 0x000c /* Max Memory Read Byte Count */
#define PCI_X_CMD_MAX_SPLIT 0x0070 /* Max Outstanding Split Transactions */
-#define PCI_X_DEVFN 4 /* A copy of devfn. */
-#define PCI_X_BUSNR 5 /* Bus segment number */
-#define PCI_X_STATUS 6 /* PCI-X capabilities */
-#define PCI_X_STATUS_64BIT 0x0001 /* 64-bit device */
-#define PCI_X_STATUS_133MHZ 0x0002 /* 133 MHz capable */
-#define PCI_X_STATUS_SPL_DISC 0x0004 /* Split Completion Discarded */
-#define PCI_X_STATUS_UNX_SPL 0x0008 /* Unexpected Split Completion */
-#define PCI_X_STATUS_COMPLEX 0x0010 /* Device Complexity */
-#define PCI_X_STATUS_MAX_READ 0x0060 /* Designed Maximum Memory Read Count */
-#define PCI_X_STATUS_MAX_SPLIT 0x0380 /* Design Max Outstanding Split Trans */
-#define PCI_X_STATUS_MAX_CUM 0x1c00 /* Designed Max Cumulative Read Size */
-#define PCI_X_STATUS_SPL_ERR 0x2000 /* Rcvd Split Completion Error Msg */
+#define PCI_X_CMD_VERSION(x) (((x) >> 12) & 3) /* Version */
+#define PCI_X_STATUS 4 /* PCI-X capabilities */
+#define PCI_X_STATUS_DEVFN 0x000000ff /* A copy of devfn */
+#define PCI_X_STATUS_BUS 0x0000ff00 /* A copy of bus nr */
+#define PCI_X_STATUS_64BIT 0x00010000 /* 64-bit device */
+#define PCI_X_STATUS_133MHZ 0x00020000 /* 133 MHz capable */
+#define PCI_X_STATUS_SPL_DISC 0x00040000 /* Split Completion Discarded */
+#define PCI_X_STATUS_UNX_SPL 0x00080000 /* Unexpected Split Completion */
+#define PCI_X_STATUS_COMPLEX 0x00100000 /* Device Complexity */
+#define PCI_X_STATUS_MAX_READ 0x00600000 /* Designed Max Memory Read Count */
+#define PCI_X_STATUS_MAX_SPLIT 0x03800000 /* Designed Max Outstanding Split Transactions */
+#define PCI_X_STATUS_MAX_CUM 0x1c000000 /* Designed Max Cumulative Read Size */
+#define PCI_X_STATUS_SPL_ERR 0x20000000 /* Rcvd Split Completion Error Msg */
+#define PCI_X_STATUS_266MHZ 0x40000000 /* 266 MHz capable */
+#define PCI_X_STATUS_533MHZ 0x80000000 /* 533 MHz capable */
+
+/* Extended Capabilities (PCI-X 2.0 and Express) */
+#define PCI_EXT_CAP_ID(header) (header & 0x0000ffff)
+#define PCI_EXT_CAP_VER(header) ((header >> 16) & 0xf)
+#define PCI_EXT_CAP_NEXT(header) ((header >> 20) & 0xffc)
+
+#define PCI_EXT_CAP_ID_ERR 1
+#define PCI_EXT_CAP_ID_VC 2
+#define PCI_EXT_CAP_ID_DSN 3
+#define PCI_EXT_CAP_ID_PWR 4
+
+/* Advanced Error Reporting */
+#define PCI_ERR_UNCOR_STATUS 4 /* Uncorrectable Error Status */
+#define PCI_ERR_UNC_TRAIN 0x00000001 /* Training */
+#define PCI_ERR_UNC_DLP 0x00000010 /* Data Link Protocol */
+#define PCI_ERR_UNC_POISON_TLP 0x00001000 /* Poisoned TLP */
+#define PCI_ERR_UNC_FCP 0x00002000 /* Flow Control Protocol */
+#define PCI_ERR_UNC_COMP_TIME 0x00004000 /* Completion Timeout */
+#define PCI_ERR_UNC_COMP_ABORT 0x00008000 /* Completer Abort */
+#define PCI_ERR_UNC_UNX_COMP 0x00010000 /* Unexpected Completion */
+#define PCI_ERR_UNC_RX_OVER 0x00020000 /* Receiver Overflow */
+#define PCI_ERR_UNC_MALF_TLP 0x00040000 /* Malformed TLP */
+#define PCI_ERR_UNC_ECRC 0x00080000 /* ECRC Error Status */
+#define PCI_ERR_UNC_UNSUP 0x00100000 /* Unsupported Request */
+#define PCI_ERR_UNCOR_MASK 8 /* Uncorrectable Error Mask */
+ /* Same bits as above */
+#define PCI_ERR_UNCOR_SEVER 12 /* Uncorrectable Error Severity */
+ /* Same bits as above */
+#define PCI_ERR_COR_STATUS 16 /* Correctable Error Status */
+#define PCI_ERR_COR_RCVR 0x00000001 /* Receiver Error Status */
+#define PCI_ERR_COR_BAD_TLP 0x00000040 /* Bad TLP Status */
+#define PCI_ERR_COR_BAD_DLLP 0x00000080 /* Bad DLLP Status */
+#define PCI_ERR_COR_REP_ROLL 0x00000100 /* REPLAY_NUM Rollover */
+#define PCI_ERR_COR_REP_TIMER 0x00001000 /* Replay Timer Timeout */
+#define PCI_ERR_COR_MASK 20 /* Correctable Error Mask */
+ /* Same bits as above */
+#define PCI_ERR_CAP 24 /* Advanced Error Capabilities */
+#define PCI_ERR_CAP_FEP(x) ((x) & 31) /* First Error Pointer */
+#define PCI_ERR_CAP_ECRC_GENC 0x00000020 /* ECRC Generation Capable */
+#define PCI_ERR_CAP_ECRC_GENE 0x00000040 /* ECRC Generation Enable */
+#define PCI_ERR_CAP_ECRC_CHKC 0x00000080 /* ECRC Check Capable */
+#define PCI_ERR_CAP_ECRC_CHKE 0x00000100 /* ECRC Check Enable */
+#define PCI_ERR_HEADER_LOG 28 /* Header Log Register (16 bytes) */
+#define PCI_ERR_ROOT_COMMAND 44 /* Root Error Command */
+#define PCI_ERR_ROOT_STATUS 48
+#define PCI_ERR_ROOT_COR_SRC 52
+#define PCI_ERR_ROOT_SRC 54
+
+/* Virtual Channel */
+#define PCI_VC_PORT_REG1 4
+#define PCI_VC_PORT_REG2 8
+#define PCI_VC_PORT_CTRL 12
+#define PCI_VC_PORT_STATUS 14
+#define PCI_VC_RES_CAP 16
+#define PCI_VC_RES_CTRL 20
+#define PCI_VC_RES_STATUS 26
+
+/* Power Budgeting */
+#define PCI_PWR_DSR 4 /* Data Select Register */
+#define PCI_PWR_DATA 8 /* Data Register */
+#define PCI_PWR_DATA_BASE(x) ((x) & 0xff) /* Base Power */
+#define PCI_PWR_DATA_SCALE(x) (((x) >> 8) & 3) /* Data Scale */
+#define PCI_PWR_DATA_PM_SUB(x) (((x) >> 10) & 7) /* PM Sub State */
+#define PCI_PWR_DATA_PM_STATE(x) (((x) >> 13) & 3) /* PM State */
+#define PCI_PWR_DATA_TYPE(x) (((x) >> 15) & 7) /* Type */
+#define PCI_PWR_DATA_RAIL(x) (((x) >> 18) & 7) /* Power Rail */
+#define PCI_PWR_CAP 12 /* Capability */
+#define PCI_PWR_CAP_BUDGET(x) ((x) & 1) /* Included in system budget */

/* Include the ID list */

@@ -403,6 +474,8 @@
unsigned short vendor_compatible[DEVICE_COUNT_COMPATIBLE];
unsigned short device_compatible[DEVICE_COUNT_COMPATIBLE];

+ int cfg_size; /* Size of configuration space */
+
/*
* Instead of touching interrupt line and base address registers
* directly, use the values stored here. They might be different!
@@ -602,6 +675,7 @@
struct pci_dev *pci_find_class (unsigned int class, const struct pci_dev *from);
struct pci_dev *pci_find_slot (unsigned int bus, unsigned int devfn);
int pci_find_capability (struct pci_dev *dev, int cap);
+int pci_find_ext_capability (struct pci_dev *dev, int cap);
struct pci_bus * pci_find_next_bus(const struct pci_bus *from);

struct pci_dev *pci_get_device (unsigned int vendor, unsigned int device, struct pci_dev *from);
@@ -768,6 +842,7 @@
static inline int pci_register_driver(struct pci_driver *drv) { return 0;}
static inline void pci_unregister_driver(struct pci_driver *drv) { }
static inline int pci_find_capability (struct pci_dev *dev, int cap) {return 0; }
+static inline int pci_find_ext_capability (struct pci_dev *dev, int cap) {return 0; }
static inline const struct pci_device_id *pci_match_device(const struct pci_device_id *ids, const struct pci_dev *dev) { return NULL; }

/* Power management related routines */